Since I did a table for this week's RPG Challenge on Reddit, I'm going to cheat a little and just repost it here. The exact text of the challenge, if you're interested:

This week's challenge is And behind this door...

For this challenge I want you to come up with alternate
dimensions/planes/realities. Imagine you have a party of adventurers
hanging out in Sigil or Sliding through space and time, what will they
find after they pass through that door or take the next jump?

Behind the door is an alternate reality. Roll on the table to see what's alternate about it:

The characters are replaced by the players, who are LARPing their characters in the game world.

The characters are replaced by the players, who are LARPing their characters in our world.

Something's just not quite right. Each player passes his
character sheet to the player to his left, who then tries to play the
character faithfully.

The world the characters believe to be reality is actually just a
shared delusion. The characters are actually all asylum inmates.

Cartoon version of game world. (with cartoon reality rules, so
characters can change the scene by pulling down a new background or the
GM can add things to the scene by having a giant pencil come down and
draw them, for example).

Claymation version of game world. (With claymation reality, so characters who die get flattened)

The PCs find themselves in our world, untranslated (so the Barbarian is still a Barbarian).

The PCs find themselves in our world, where they are actors who play the roles of their characters in a movie or TV show.

Video Game Reality. Everything is CG and there are power-ups and other video game tropes (think Scott Pilgrim).

The world is the same, but in this version of it the characters
never became adventurers. They're blacksmiths or accountants or
something with boring, normal lives. Of course, something will probably
happen to change that...

The world is the same, but the characters all took different
paths. Each player re-creates his character as a member of the
Class/Job/Archetype of the player on his left, but the character's basic
personality stays the same.

The world is the same, but the characters have somehow attained great power--they're kings, popes, guildmasters, generals, etc.

The door leads to another time. 1d20x10 years in the past.

Another time door: 1d20x10 years in the future.

Greater time door: 1d20x100 years in the past.

Greater time door: 1d20x100 years in the future.

Shades of Gray: The players find themselves in a Film Noir version of the game world.

Square Jawed Men of Action: The players find themselves in a Pulp version of the game world.

Why I Oughtta: The players find themselves in a Slapstick version of the game world.